Humidifying systems are generally known for controlling humidity in a paint or lacquer room. A humidifying system may, for example, include a compressed-air sprayer which works according to the Venturi principle in which compressed air with a relatively high pressure sucks in water with a relatively low pressure through an input valve. In order to keep the pressure of the compressed air that is being used at a particular desired constant level, the system is also fitted with compressed-air pressure regulators to regulate the pressure of the compressed air that is to be inputted. Correspondingly, in order for the water pressure to be kept at a particular desired constant level, the system is fitted with water pressure regulators for regulating the pressure of the water that is to be inputted. These compressed-air pressure regulators and water pressure regulators ensure that any variations there may be in the pressure of the compressed air and/or water pressure that is to be inputted are not passed on to the compressed-air sprayer. In this way, any disruption to the processing conditions in the compressed-air sprayer can be counteracted. Equipment such as this is also fitted with at least one humidity sensor for measuring the humidity of the air that is already humidified or is to be humidified. Depending upon the humidity that is picked up by the humidity sensor, the compressed-air sprayer (of which there is at least one) will be switched on or off by the controls. If a number of compressed-air sprayers are fitted, a large or small number of them may be switched on or off, depending on the humidity that is picked up by the humidity sensor.
Known humidifying systems generally have a number of disadvantages. Each of the compressed-air sprayers is set up so that when it is active it sprays water which basically has the same size of drops under any processing conditions. Depending on the exact processing conditions, when spraying takes place these drops will evaporate to some degree, be it greater or lesser. When processing conditions are less favorable, the drops which remain unevaporated will usually be large in size, and these will often need to be caught using separate drip catchers. The drops which remain unevaporated do not actually make any contribution to increasing the humidity of the air that is to be humidified. This means that the yield of such humidifying systems is relatively low. From a certain size upwards, the large drops will either precipitate or condense on their own or will be caught in a drip catcher if one is applied. The water that is obtained in this way is drain water that can generally be removed. The drawback of recirculating this drain water (i.e., using it for spraying again) is that spraying it has many undesired characteristics such as encouraging the growth and spread of bacteria. Harmful effects such as these may, of course, be counteracted by purifying the drain water, for example. This, however, increases costs and certainly cannot always be achieved satisfactorily. Discharging the drain water into surface water or into sewers is increasingly being prohibited or adds additional cost. As will be clear, from the point of view of costs, purifying drain water before it is to be discharged is disadvantageous.